Bulkhead door and the like



March 22, 1938. J. F. TUCKER 2 7 BULKHEAD DOOR AND THE LIKE Filed Feb. 12, 1936 2 Sheets-Sheet l fl Hi HHHIHHHHHIHHHHHHHHH \H WK. 22, 1938.. J. F. TUCKER 2,113,877

BULKHEAD DOOR AND THE LIKE Filed Feb. 12, 1956 2 Sheets-Sheet 2 Patented Mar. 22, 1938 UNITED STATES FATE orrlce BULKHEAD noon AND THE LIKE Joseph Francis Tucker,

Little Thrift, Petts of Great Britain Application February 12, 1936, Serial No. cases In Great Britain February 14, 1935 6 Claims.

This invention concerns improvements relating to driving means for the operation of ships bulkhead or anti-piracy doors. I

With a bulkhead door a high initial resistance has generally to be overcome in withdrawing the door from wedges upon opening, particularly if the natural wedging elTect from the previous closure is accentuated by the presence of dirt or by distortion of the bulkhead or seating. Once the door is started from the wedges, however, the resistance to be overcome is much smaller. The driving means must naturally be capable of overcoming the high initial resistance.

This dilficulty has proved a serious obstacle to r: the general adoption of electrical driving means lo for bulkhead doors-a purpose for which such driving means is otherwise highly advantageous. The difficulty is pronounced in this case because the installation of electrically actuated bulkhead doors is economically feasible only if the high speed driving motors can be made small and in expensive and if the switch-gear can be made relatively simple. a

It is a particular object of the invention to furnish a driving arrangement which satisfies the last-named requirements, that'is, an arrangement combining the advantage of operation by an elec-- tric 'motor of economical size and power with that of control by simple but effective switch-- gear.

According to the invention, bulkhead-door apparatus comprises a sliding door and a door frame having wedging engagement in the closed position of the door, an electric motor, transmission gearing connected to the said motor, assisting mechanism through which the said gearing is connected to the door, such mechanism including mechanical-advantage means connected to the door and a lost-motion device connecting the gearing and adapted for being actuated by the latter in the direction for producing effective operation of the mechanical advantage means in the initial'stage only of a door-opening opera-- said mechanical-advantage means to the said out any starting resistance or complicated switch gear.

By mechanical advantage means is to be understood.- lever or screw means, which are preferred, or wedge, cam or like means.

The control device for switching off the motor is preferably adapted for sodoing whenever the lost motion device is reversely actuated during the closing of the door, whether the latter is arrested normally at the end of such closing or at an intermediate point due, for example, to some obstacle. Thus, the control device may comprise a switch adapted for being operated by a strip: member arranged beside the apparatus in the path of a part operatively connected with the lost motion device.

As will be readily understood, the driving means may, if desired, be devised for giving a transmission which is operative in more than two stages having different mechanical advantages.

Various embodiments of the invention by way of example will now be described with reference to the accompanying drawings, in which:

Fig. 1 shows an electrically operated, vertically sliding, bulkhead door,

Fig. 2 a modification,

Fig. 3 an electrically operated, horizontally sliding door,

Figs. 4 and 5 are a front elevation and vertical section of an alternative arrangement,

Fig. 6 shows a modification, and

Fig. '7 is a circuit diagram, of electrical gear to be employed with any of the arrangements illustrated in Figures 1 to 6.

Fig, 1 illustrates a bulkhead door I of the vertically sliding type driven from an electric motor 2 through worm reduction gearing 3 and a screw 5 and nut 5. For the purposes of the present invention, the nut 5 is a prismatic nut, advantageously of high-tensile bronze, which is slidable vertically in a box-like guide 6 at the top of one face of the door panel, the said guide being sufficiently deep to permit the nut 5 to travel a certain distance up the screw 4, in an opening direction, before it encounters the top-wall l of the guide. Extending into recesses 8 in the sides of the nut through slots 9 in theside walls of the guide 6 are two substantially horizontal levers l8 pivoted at l! upon bosses on the door panel and projecting beyond their pivots towards the uprights l2 of the door-frame. In the (illustrated) closed position of the door I, the ends of the levers ll) lie just above stops l3 fixed to the uprights H. In the levers Hi, the distances of the nut 5 and the pivot H from the stop l3 will be in a substantial ratio, say between three and six to one or greater if necessary.

Let it be assumed that the door I is closed tightly in its Wedges l4 and that the nut 5 is at the lower part of its travel in the guide 6. Upon rotating the screw 4 in the direction for opening the door, the nut initially travels up the screw in the guide. In this lost motion, it rocks the levers about their pivots l I and into contact with the stops l3 and then rocks the said levers about the said stops as fulcra, so applying a lifting force to the door, by way of the pivots H, with a substantial mechanical advantage (e. g. 36:1) over and above that of the screw and nut mechanism. This should be sufficient to ensure the dislodgement of the door from its wedges. The nut 5, rising further in the guide 6, eases the door out of the wedges for a fraction of an inch by means of the levers I and then abuts against the top 1 of the guide and directly transmits a lift to the door at normal speed until the open position is: reached. The uppermost position of the nut and guide is indicated by a broken line.

Thus a large force is applied for a small initial amount of travel of the door and a smaller force, suited to the normal resistance and required speed of opening of the door, for the rest of its travel.

Upon closing the door, the operation is normal except that the nut finally moves to the lower limit of its travel in the guide 6 in preparation for the next lifting operation. For various reasons, e. g. to provide a cushioning effect and to safeguard the door and mechanism should the former be closed too forcibly, it is advantageous to provide a spring or springs which will tend to resist downward travel of the nut in the guide. As illustrated, a compression spring 15 is arranged in the guide 8 beneath the nut 5. Alternatively, as illustrated in Fig. 2, a separate compression spring 16 may be arranged between each lever and a convenient abutment H on the door. With either arrangement, when the closing door has reached its wedges Hi, the nut will cause the spring or springs to be compressed, putting a predetermined even pressure on the door in addition to its weight and thus ensuring firm closure.

Precisely the same arrangement can be em ployed with a horizontally sliding or travelling door. With the common arrangement illustrated in Fig. 3, employing two operating screws 4, each nut 5 is arranged to operate one of the levers Hi. In the case of a horizontally moving door, the spring or springs should be sufficiently stiif to transmit the closing force to the door until the wedges are encountered. As illustrated in Fig. 3, the levers H] are provided with ball-heads H3 engaging in grooves 8 on the faces of the nuts 5.

Similar arrangements may be employed in the case of doors operated from an electric motor through reduction gearing and one or more racks and pinions. As illustrated in Figs. 4 and 5, the levers l0 may be arranged to engage in a slot or recess 8 in the rack l8 andthe latter is allowed a restricted amount of sliding movement in relation to the door-panel in a guide 19 on the latter. A roller 20 assists in taking up the thrust of the driving pinion 2 I. Alternatively the levers may be arranged to engage with the rack or racks near the closing end of the door (the bottom of a vertically sliding door) and to co-operate with stop-means disposed at the closing end of the frame (the bottom frame-bar for a vertically sliding door).

With any of the arrangements described above, it may be preferred to transmit the initial opening force not through the pivots I I, but by way of ample co-acting thrust surfaces 22, 23 (Fig. 6) formed upon the levers l0 and the door panel.

The above described mechanisms for giving the large initial mechanical advantage are believed to be the most suitable for electrically operated bulkhead doors. They may, however, be replaced by the mechanism described in connection with a valve in the specification of my patent application, Serial No. 125,168.

With any of these mechanisms, a motor of high power is not required. Thus a motor of about 2 H. P. should be capable of operating practically any bulkhead door at the normally required speed. A motor of such low power can be switched directly on to the mains, without any complicated starting resistance, by contactor switchgear 24 controlled by a local switch 25, a master-switch 26 on the bridge and, if desired, a master switch H at the margin-line, and limit-switches 28, 29 associated with the door. The local switch 25, which has a handle on each side of the bulkhead, may have three positions: (1) A normal position in which it prepares, at 30, a circuit for the closing winding 24 of the contactor switch-gear to be completed by way of the master-switch 26 or 21 and the limit switch 28: (2) A door-closing position in which it breaks the aforesaid circuit and establishes, at 3!, a circuit for the closing winding 2& directly through the aforesaid limit switch: (3) A door-opening position in which it establishes, at 32, a circuit for the opening winding 24 of the contactor switch-gear through the limit switch 29.

The limit switch 28 is preferably arranged so that it is opened, not only when the door is closed, but also if the door is impeded by an obstacle. Referring again to Fig. 1, it will be appreciated that the nut 5 will take up its initial travel against the resistance of the spring I5 whether the closing door is arrested by the wedges M or by some foreign obstacle to its closure. To ensure that the switch 28 is opened in these latter circumstances, it is arranged to be operated upon the taking up of the initial travel of the nut. As illustrated in Fig. 1, one of the levers I0 has an arm 33 which is swung out, when the aforesaid nut-travel is taken up, into contact with a long strip 34 disposed beside the path of the door and arranged so that it opens the switch 28 when it is depressed by the contact of the arm 33 with any part of it. Thus the motor 2 is switched ofi whether the door is arrested by its wedges or an obstacle. In the case of an obstacle which yields slowly under the weight of the door and the compression of the spring l5, the door will follow the yielding obstacle whilst the nut will remain stationary, so that the arm 33 will gradually rock until the strip 34 allows the switch 28 to reclose and restart the motor. The nut 5 will then be driven downwardly once more until the switch 28 is again opened, the cycle being repeated until yielding ceases or the door is closed. In this way, damage to the motor upon the door encountering an obstacle isprevented, although the door is permitted to follow if the obstacle yields. The arm 33 may be replaced by various other means, for example a separate bellcrank lever 35 (Fig. 2) mounted on the door above or below the lever ii] and. adapted for being rocked by the latter through a push-rod 36, link or the like. 1

If desired, the switch 28 may be provided in addition to and connected in series with a limit switch conventionally disposed at 31. As illustrated in Fig. 7, however, the switch 31 controls only an indicating lamp 38 at the bridge and,

' possibly, .another at the margin line, forming part of the usual indicating and warning means.

Such mechanisms can be associated without difiiculty with the usual hand-gear. In Fig. 1, a local-handle or hand-wheel 39 operates a shaft 40 which may also be extended up to hand-gear on deck. This shaft 40 is normally coupled to the screw 4 by a clutch 4|. The clutch is controlled by a solenoid 42 connected in series with the motor 2 and arranged to de-clutch the handgear whenever the motor is energized. A slightly modified arrangement is shown in Fig. 3. The

clutch may be dispensed with if the lead to the hand-gear is short.

I claim:-

1. Bulkhead-door apparatus comprising a sliding door, a door frame having wedging engagement with the door in the closed position of the door, an electric motor, transmission gearing connected to the said motor, assisting mechanism connecting said gearing to the door, said assisting mechanism including mechanical advantage means connected to the door and a lost-motion deyice connecting the said mechanical-advantage means to the said gearing for being actuated by the latter in the direction for producing efiective operation of the mechanical advantage means in the initial stage only of a door-opening operation, when the high resistance of the wedging engagement has to be overcome, and for being actuated in the opposite direction during the door-closing operation, and switch-means electrically connected to the motor and positioned so as to be engaged and operated by the assisting mechanism to switch oif the motor after the actuation of the lost-motion device in the said opposite di rection.

2. Bulkhead-door apparatus comprising a sliding door, a door frame having wedging engagement with the door in the closed position of the door, an electric motor, transmission gearing connected to said motor, assisting mechanism connecting the said gearing to the door, said assisting mechanism including lever-means carried by the door and engageable with the frame when the door is in the closed position, and a lost motion device connecting the said lever-means to the said gearing for being actuated by the latter in the direction for producing effective operation of the lever-means in the initial stageonly of a door-opening operation, when the high resistance of the wedging engagement has to be overcome, and for being actuated in the opposite direction during the door-closing operation, and switchmeans electrically connected to the motor and arranged for being engaged and operated by the lever means in such fashion as to switch oif the motor after the actuation of the lost-motion device in the said opposite direction.

3. Bulkhead-door apparatus comprising a sliding door, a door frame having wedging engagement with the door in the closed position of the door, an electric motor, transmission gearing con nected to the said motor, assisting mechanism connecting the said gearing to the door, said assisting mechanism including mechanical-advantage means connected to the door, a lost-motion device connecting the said mechanical-advantage means to the said gearing for being actuated by the latter in the direction for producing effective operation of the mechanicaladvantage means in the initial stage only of a door-opening operation, resilient means arranged for assisting the first-named actuation of the lost-motion device and for resisting the opposite actuation thereof, and switch-means electrically connected to the motor and arranged for being engaged and operated by the assisting mechanism in such fashion as to switch off the motor after the actuation of the lost-motion device in the said opposite direction.

4. Bulkhead-door apparatus comprising a sliding door, a door frame having wedging engagement in the closed position of the door, an electric motor, transmission gearing connected to the said motor and door, mechanical advantage means connected to the said gearing and operative for assisting movement of the said door by the said gearing inv the initial stage only of a door-opening operation when the high resistance of the wedging engagement has to be overcome, electric supply mains for the motor, and control switchgear arranged for being operated by the mechanical advantage means for connecting the said motor directly to the said mains.

5. Bulkhead-door apparatus according to claim 4 wherein the control-switchgear comprises a contactor-switch adapted for connecting the motor directly to the supply mains and a switch disposed in the exciting circuit of the contactorswitch, said switch being positioned in the path of movement of the mechanical advantage means so as to be operated thereby.

6. Bulkhead-door apparatus comprising a sliding door, a door frame having wedging engagement with said door in the closed position of the door, an electric motor, transmission gearing connected to the said motor, assisting mechanism carried by the door and connecting the gearing to the door for being actuated by the gearing to assist movement of the door in the initial stage only of a door-opening operation. when the high resistance of the wedging engagement has to be overcome, and for being reversely actuated upon arrest of the door at any point in a door-closing operation, a motor-control switch. a first switch-operating member connected to the assisting mechanism so as to be actuated therewith and also to be moved bodily with the door, and a second switch-operatingmember of strip form disposed beside the path of bodily movement of the first member and engageable thereby for effecting switching off of the motor upon reverse actuation of the assisting mechanism at any point in the door-closing operation.

JOSEPH FRANCIS TUCKER. 

